Alternative refrigerants such as HFC-125 (CF3CHF2) and HFC-134a (CF3CH2F) have been widely used as important replacements for CFC, HCFC, etc., which destroy the ozone layer. However, these alternative refrigerants are potent global warming substances, thus creating concern that their diffusion may affect global warming. To combat this, these refrigerants are collected after use; however, not all of them can be collected, and their diffusion due to, for example, leakage cannot be ignored. Although the use of CO2 or hydrocarbon-based substances as alternative refrigerants has also been studied, CO2 refrigerants have many difficulties in reducing comprehensive greenhouse gas emissions, including energy consumption, because of the requirement of large equipment due to the low efficiency of the CO2 refrigerants. Hydrocarbon-based substances have safety problems due to their high flammability.
Haloolefin compounds containing fluorine groups with a low warming potential are attracting attention as substances that can solve these problems. Known examples of haloolefin compounds containing fluorine groups include 1233xf (CF3CCl═CH2). 1233xf, used alone or in combination with other substances, such as hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs), is expected to be useful as a refrigerant, and additionally as a blowing agent, propellant, extinguishing agent, or the like. 1233xf is also important as a raw material for producing other hydroolefin compounds such as HFO-1234 yf, which is expected to be used for a refrigerant etc., or as a raw material for producing HCFC-244bb or like other hydrofluoroolefin precursors. Various 1233xf production methods are known. For example, a method in which 1,1,1,2,3-pentachloropropane (240db) or the like is used as a starting material, and reacted with hydrogen fluoride (HF) in the presence of a catalyst is known.
For example, Patent Literature 1 discloses a technique of adding a polymerization inhibitor to 1,1,2,3-tetrachlolopropene in the production of 1233xf and 1,1,1,2-tetrafluoropropene by a reaction of 1,1,2,3-tetrachloropropene and hydrogen fluoride in the presence of a catalyst. By thus adding a polymerization inhibitor as a stabilizer, the lifetime of the catalyst can be extended, thereby increasing the production efficiency of 1233xf and 1,1,1,2-tetrafluoropropene. 1,1,2,3-tetrachloropropene or the like used as a starting material may produce a byproduct by being decomposed or polymerized during storage or reaction. It is assumed that adhesion of the byproduct to the surface of the catalyst deactivates the catalyst. In the technique disclosed in Patent Literature 1, when the starting material is decomposed during storage or reaction, thereby producing an active intermediate such as a radical or an acid component (may be referred to as “radical etc.” hereinafter), the radical etc. is captured by a polymerization inhibitor, which serves as a stabilizer. The lifetime of the catalyst can be extended presumably because such capture inhibits a decomposition reaction or a polymerization reaction of the starting material.